Cook macaroni according to package directions. Drain, set aside.
In a saucepan over medium heat, melt butter. Add all-purpose flour and stir to combine, creating a paste. Cook for 1 minute. Add milk and whisk constantly to combine. Continue cooking about another minute, or until mixture thickens slightly.
Reduce heat to low. Add salt, paprika, and ground black pepper. Stir to combine. Add mac and cheese shredded cheese and stir until cheese is melted and fully incorporated. Remove from heat.
Add sour cream and stir until combined. Add drained macaroni and bacon pieces (optionally, reserve a small amount for topping) and stir to combine.
Rinse and dice green onions. Serve macaroni and cheese, top with green onions, reserved bacon pieces, a dollop of sour cream, and more mac & cheese shredded cheddar cheese.
